The invention is described below, in particular, with regard to retrofit lamps, in particular retrofit LED lamps. However, it should be understood that other, accordingly configured operational devices for luminous means are also intended to be included.
For retrofit lamps, it is important that they can be used to simulate substantially the functionalities known from incandescent lamps. One of these known functionalities is the dimming function. Dimming is conventionally in the form of phase dimming, which entails various problems, in particular when using retrofit LED lamps.
In common LED lamps, dimming is usually carried out via separate control lines by transmitting an item of dimming information, for example a dimming level value, to the LED lamp. This is not possible in the retrofit sector since the required control lines are not already present, but rather there is only a two-wire connection to the lamp.
Lamps which can be switched to two discrete lighting modes by means of particular switch-on/switch-off sequences of an operating voltage or mains voltage are known. Such a lamp according to the prior art can be switched, by means of a simple switching-on operation, to a first lighting mode in which the lamp is operated at full power until being switched off. A sequence of switching-on/switching-off operations which take place in quick succession, for example on-off-on, can be used to switch the lamp to a second lighting mode in which the lamp is operated, for example, at a predetermined lower power, that is to say in a dimmed manner. A switching-off operation returns the lamp to the initial state again, from which either the first or the second lighting mode can be selected again.
This functionality is also known under the term “double click” in which the lamp evaluates rapid, repeated switching (for example twice) of the operating voltage on and off as information, in particular dimming information. If the operating voltage is rapidly switched on and off twice, the ballast electronics of the luminous means therefore interpret that the lamp is operated at reduced power (dimmed).
However, only two predetermined lighting modes are available in the known lamps and the user can only choose between these lighting modes (for example 100% power or 80% power). If dimming to another level is desired, another lamp must be chosen and/or the lamp must be replaced.